This passage holds the just punishment for those spiritual slave-holders...

The Sins of Babylon

I saw that since the second angel proclaimed the fall of the churches, they have been growing more and more corrupt. They bear the name of being Christ's followers; yet it is impossible to distinguish them from the world. Ministers take their texts from the Word of God, but preach smooth things. To this the natural heart feels no objection. It is only the spirit and power of the truth and the salvation of Christ that are hateful to the carnal heart. There is nothing in the popular ministry that stirs the wrath of Satan, makes the sinner tremble, or applies to the heart and conscience the fearful realities of a judgment soon to come. Wicked men are generally pleased with a form of piety without true godliness, and they will aid and support such a religion. {EW 273.1}
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I saw that since Jesus left the holy place of the heavenly sanctuary and entered within the second veil, the churches have been filling up with every unclean and hateful bird. I saw great iniquity and vileness in the churches; yet their members profess to be Christians. Their profession, their prayers, and their exhortations are an abomination in the sight of God. Said the angel, "God will not smell in their assemblies. Selfishness, fraud, and deceit are practiced by them without the reprovings of conscience. And over all these evil traits they throw the cloak of religion." I was shown the pride of the nominal churches. God is not in their thoughts; their carnal minds dwell upon themselves; they decorate their poor mortal bodies, and then look upon themselves with satisfaction and pleasure. Jesus and the angels look upon them in anger. Said the angel, "Their sins and pride have reached unto heaven. Their portion is prepared. Justice and judgment have slumbered long, but will soon awake. Vengeance is Mine, I will repay, saith the Lord." The fearful threatenings of the third angel are to be realized, and all the wicked are to drink of the wrath of God. An innumerable host of evil angels are spreading over the whole land and crowding the churches. These agents of Satan look upon the religious bodies with exultation, for the cloak of religion covers the greatest crime and iniquity. {EW 274.1}

All heaven beholds with indignation human beings, the workmanship of God, reduced by their fellow men to the lowest depths of degradation and placed on a level with the brute creation. Professed followers of that dear Saviour whose compassion was ever moved at the sight of human woe, heartily engage in this enormous and grievous sin, and deal in slaves and souls of men. Human agony is carried from place to place and bought and sold. Angels have recorded it all; it is written in the book. The tears of the pious bondmen and bondwomen, of fathers, mothers, and children, brothers and sisters, are all bottled up in heaven. God will restrain His anger but little longer. His wrath burns against this nation and especially against the religious bodies that have sanctioned this terrible traffic and have themselves engaged in it. Such injustice, such oppression, such sufferings, are looked upon with heartless indifference by many professed followers of the meek and lowly Jesus. And many of them can themselves inflict, with hateful satisfaction, all this indescribable agony; and yet they dare to worship God. It is solemn mockery; Satan exults over it and reproaches Jesus and His angels with such inconsistency, saying, with hellish triumph, "Such are Christ's followers!" {EW 275.1}

These professed Christians read of the sufferings of the martyrs, and tears course down their cheeks. They wonder that men could ever become so hardened as to practice such cruelty toward their fellow men. Yet those who think and speak thus are at the same time holding human beings in slavery. And this is not all; they sever the ties of nature and cruelly oppress their fellow men. They can inflict most inhuman torture with the same relentless cruelty manifested by papists and heathen toward Christ's followers. Said the angel, "It will be more tolerable for the heathen and for papists in the day of the execution of God's judgment than for such men." The cries of the oppressed have reached unto heaven, and angels stand amazed at the untold, agonizing sufferings which man, formed in the image of his Maker, causes his fellow man. Said the angel, "The names of the oppressors are written in blood, crossed with stripes, and flooded with agonizing, burning tears of suffering. God's anger will not cease until He has caused this land of light to drink the dregs of the cup of His fury, until He has rewarded unto Babylon double. Reward her even as she rewarded you, double unto her double according to her works; in the cup which she hath filled, fill to her double." {EW 275.2}

I saw that the slave master will have to answer for the soul of his slave whom he has kept in ignorance; and the sins of the slave will be visited upon the master. ...